: oLpae Tt ‘ a Rae 
IX.] ABOUT MOSSES AND LICHENS. 145 
have distinct stem and leaves, like the mosses, though 
the leaves are of a more delicate texture, and lack 
the mid-rib which many of the mosses possess. The 
sermination of the spores is similar to that of mosses. 
The Liverworts (AZarchantiace@) have no distinct 
stem or leaves, but consist of a flat, horizontal 
cellular frond, attached by tiny rootlets from the 
under surface. There are but nine British species, 
the most plentiful of which is the Common Liver- 
wort (Warchantia polymorpha), which will serve to 
illustrate the order. It is very common in all moist 
Fic. 110. 
Fic. 109. 
situations, its dull green fronds covering patches of 
earth. The organs of reproduction are borne upon 
stalks. The antheridia and archegonia are produced 
on separate plants. -The antheridia receptacle is 
shown in fig. 109. It is slightly concave on the upper 
surface, and studded with the openings of the anther- 
idia, which are embedded in its substance (fig. 110, 
section). They contain the antherozoids, which, on 
being set free, enter and fertilise the archegonia, 
which give rise to the sporangia shown in fig. III. 
The spore cases are arranged on the under surface 
K 
